The wings of many different types of aircraft are equipped with high lift devices that are operable to increase the lift experienced by an aircraft wing. Such high lift devices may allow the wing to operate at a higher angle of attack.
An example of a high lift device is a slat. In use, a slat may be moved away from the leading edge of the fixed wing of an aircraft, thereby creating a gap between the slat and the wing under slat surface. Deploying slats in this way tends to allow an aircraft to fly at slower speeds, or take off and land in shorter distances.
A different, separate example of a high lift device is a leading edge flap, or a droop. Droops are leading edge sections that rotate downwards relative to a fixed aircraft wing. In contrast to a slat, the droop does not move away from the wing leading edge when it is deployed, and thus no gap between the droop and the wing under flap surface is created.
U.S. Pat. No. 4,399,970 discloses a wing leading edge slat actuation and positioning system. The system having a number of positions:—a stowed or retracted position; a first operative position where the upper surface of the slat and the upper surface of the fixed wing section form a substantially smooth and continuous upper surface; and a further extended position where a slot is formed between the leading edge of the fixed wing portion and the trailing edge of the extended slat panel.